Commutator resurfacing and dressing tool assembly



Dec. 27, 1949 w M. M. ROSS 2,492,596

COMMUTATOR RESURFACING AND DRESSING TOOL ASSEMBLY Filed May 29, 1947 s Sheets-Sheet 1 IN VEN TOR.

Dec. 27, 1949 M. M. ROSS 2,492,596

GOMMUTATOR RESURFACING AND DRESSING TOOL ASSEMBLY Filed May 29, 1947 3 Sheets-Sheet 2 47 26 I 57 i i 46 INVENTOR. /%'/Zzzrzz flj asis' M. M. ROSS Dec. 27, 1949 'comumuon assunmcme AND mwssme TOOL ASSEMBLY Filed May 29,1947

3 Sheets-She et 3 IN VEN TOR.

flJZzz/Jz K2055 BY W I Patented Dec. 27, 1949 QQMMU'EATOR BESURFACIN G AND DRESS- ING TOOL ASSEMBLY lmbnr'n' 'Moniiomery Ross, Wichita, Kans.

29, 194-1, Serial-No. 751,403

1 Claim.

The presentinvention relates to means-for truing up and dressing the rcomrnutntonsurfaces of fractional horsepower. electric motors and generators, particularly automotive zenerators and starters.

My invention comprehends a tool assembly for completely refinishing working surfaces of commutators, whichsurfaces become so muchened by continuous contact with the brushes associated therewith as to cause excessive arcing and consequent operative inefficiency in the electric power units of which said worn commutators are parts. My assembly includes a frame for rotatabl mounting an armature Icy-the shaft there of, a set of adjustable bushings foruse with said frame enabling the latterto accommodate variously sized armature shafts, a. mount forjan electric motor or other rotary propulsion means for turning the armature in the frame. -beltand pulley means for transmitting power from the motor to the armature, anundercutting toolsub assembly mounted upon the frame for removing chips. of conductor which may wedge between the commu r nductor bars and-for undemutting the mica insulator therebetween; and. a lathe tool subassembly for refinishing the eXpoSedand-roughened surfaces of. said commutator conductor bars.

It is the principal object of my invention to pro:- vide a novel and improved-lathe and undercutting tool assembly for completely refinishing worn commutator surfaces, which assembly is compact, relatively inexpensive to mamzfacture. strong andsturdy in construction, and efilcient iii-operation Advantageously, my lathe tool sub-assembly is provided with a clamp adapted alternatively to. engage the frame of my complete assembly or the casing of an automotive generator unremoved from its vehicle of installation. Thus. the major sub-assembly of my invention'is capable oi operating as a bench tool upon thecommutator-of a disassembled. motor or generator or as a-portable tool which can. be mounted directly upon an automotive generator or starter motoriwhllesaid generator remains assembled in its vehicle. Iii-this respect my invention is new and-superior to the prior art commutator dressing devices; I am aware that among said prior art devices. there are contrivances adapted to work directly; upon au o motive installations, but none of said ccntrivances are adapted to conversion soquickly and easily from a bench tool to a Portable tool and vice versa as is my invention.

7 Accordingly, itis another objector my invention to provide a commutator twin; and; dressing d 2 of a fixed bench assembly or at the installation of the particular piece of work at hand.

The foregoing and such other objects, advantages and capabilities as may appear herein or be pointed out as this description proceeds or as are inherent in the present invention, are illustrated in the accompanying drawings, in which:

Figure l is a perspective view of my complete assembly fixed to a bench for work upon the commutator of an armature removed from its stator;

Figure 2 is a perspective view of the lathe tool sub-assembly of my invention mounted upon the casing of an assembled generator for work upon the commutator therewithin; and

Figure 3 is a detail view taken in vertical section upon the line 3-3 of Figure 2;

Figure 4 is a plan view of the frame with the undercutting and lathe tool sub-assemblies mounted thereon;

Figure 5 is a view in vertical section taken upon the. line 5-5 of Figure 4;

Figure 6 is a detail view of the lathe tool subassembly taken in vertical section upon the line 6-6 of Figure 5; and

Figure '7 is another detail view of the lathe tool sub-assembly taken in horizontal section upon the line 1-1 of Figure 6;

Y Figure 8 is an elevational view of the motor mount taken in the vertical plane of the line 8-8 of Figure 1; and

Figure 9 is a plan view of said motor mount. 7 Like reference characters are used to designate similar parts in the drawings and in the detailed description of invention which follows.

Referring now more particularly to Figure 1, my complete assembly is illustrated therein supported by a bench or other work table l9. Fixed to the bench [ii is the mount II for the electric motor I2. As is best shown in Figures 8 and 9, the base [3 of this mount II is integrally formed with a pair of upstanding, horizontally spaced flanges I4 and I5, which flanges are indented in V fashion from the top edges thereof to cradle the motor 12. Between the flanges I4 and I5 is positionedan inverted V-shaped clamping head 16. One end of the clamping head It is loosely journaled about the guide rod ll projecting upwardly of the base [3. The other end of the clamping head #6 is U-shaped to embrace the threaded eye-bolt i8 secured by the pin is to the base l3. Washers 2b and, 2| are fitted about t guide rod H a the yeebolt 18 respective y vice adapted to. operate emcientlyeither as part coabove the head It. The washer It engages a small protuberance 22 formed in the end of the guide rod l1 to limit the upward displacement of the head [6. A wing-nut 23 screwed upon the eye-bolt l8 provides means for securing the clamping head 16 down upon the motor 12.

Also fixed to the bench In a short distance from the motor mount H is the armature mounting frame 24. This frame 24 includes a base 25 supporting the bed 26. At one end of the bed 26 is fastened a rectangular way block 21 which guides the moveable journal member 28. This journal member 28 comprises a split yoke bearing 29 connected by a neck 39 to a pair of legs 3| and 32 V straddling the way block 21. The inside, oppositely-disposed faces of the legs 31 and 32 are formed with way grooves therein engaging the sides of the block 21, whereby the journal member 28 may slide back and forth upon said block for the adjustment of the frame 24 to various lengths of armature shaft. A bolt 33 and a knob 34 provide means for drawing the legs 3| and 32 together to clamp the journal member 28 immovably to the block 21.

The opposite end of the bed 26 from the movable journal member 28 is integrally formed with an upstanding, immovable journal member 35 (best shown in Figure 5) terminating in a second split-yoke bearing 36 co-axially aligned with the aforementioned bearing 29. Within the bearings 29 and 36 respectively are positioned the split bushings 31 and 38, which bushings journal the shaft 39 of the armature 40 (Figure 1). Screws 4! and 42 respectively provide means for drawing the ends of the bearings 29 and 36 together to fit tightly about the bushings 31 and 38, in turn fitting said split bushings more closely about the armature shaft 39. A set of additional bushings (not shown) similar to those designated 31 and 38, but graduated in annular thickness therefrom, may be provided with my lathe assembly to adapt the bearings 29 and 36 to shafts of various diameters.

The undercutting sub-assembly 43 (best shown in Figures 4 and 5) is supported by the bracket 44 fixed to one side of the frame 24 at the end thereof remote from the movable journal member 28. The bracket 44 is formed with two upwardly projecting arms 45 and 46, the ends of which are bored to journal the horizontal shaft 41. side thereof to the shaft 41 as indicated at 48 in Figure 5, and screws 49 and 59 thus provide means for adjusting the fitting of these split ends about the journaled shaft. This fitting should be loose enough to allow the shaft 41 to slide forward and backward in its bearings, but should also be tight enough to prevent any motion in said shaft other than that along or around its longitudinal axis.

The shaft 41' is translated back and forth by means of the operating lever 51 pivoted thereto by the bolt 52. The lever 5| is also pivoted at the lower end thereof upon the bolt 53 projecting from the bracket 44. A small amount of play must be permitted between the lever 51 and the pivot bolt 53 since the horizontal translation of the upper pivot between said lever and the shaft 41 will cause the lower end of the lever to rise and fall slightly.

The end of the shaft 41 contiguous the bearing 36 carries the cutting tool 54. The operative edge 55 of this tool 54 is disposed in the horizontal plane which also includes the central longitudinal axis of the armature shaft 39. The seat for the tool 54 is formed in the shaft 41 by out- These arms are also split inwardly from one ting away the upper cylindrical surface thereof, inclining the vertical wall of the cut at an angle other than 90 with respect to a longitudinal axis of said shaft. The end of the shaft 41 is also finished off at the same angle of inclination so that the tool 54 may be secured upon its seat by the wedging action of the washer 56 and the screw 51 (Figure 4). Now, when the tool 54 is brought to bear-upon a piece of work, the force exerted by the work against said tool, which force will be normal to the shaft 41, will not end to dislodge the tool but instead will wedge it more tightly against the washer 56.

Upon the other side of the frame '24 from the undercutting sub-assembly 43 and directly opposite thereto is positioned the lathe tool and carriage sub-assembly 58. This lathe sub-assembly 58 includes a carriage bed 59 with V-shaped guideways 60 and 61 longitudinally formed therein. Dovetailed into the guideways 66 and 6! is a base extension of the tool carriage 62. A screw 63 is threaded into a rib 64 of the carriage bed 59 and said screw is also rotatably journaled in an offset arm 65 of the tool carriage 62 (see Figure 6). Thus, when the screw 63 is rotated by means of the handle 66 affixed thereto, the tool carriage 62 will move forward or backward in the guideways 60 and 6 l. A gib 61 is positioned in the guideway 60 and set screws 68 provide means for adjusting said gib to compensate for wear in the guideways.

The tool carriage 62 is transversely pierced by the bore 69 in which is slidably paired the shank 16 of the lathe cuttingtool 1| (see Figure 7). A tool adjusting screw 12 is threaded into the carriage 62 parallel and near to the bore 63, and said screw extends into the cylindrical recess 13 formed in the carriage 62 and partially intersecting the bore 69. The end of the screw 12 within the recess 13 carries a cylindrical flange 14 which fits snugly within an arcuate slot 15 in the tool shank 1|. The outer end of the screw 12 is provided with a wing-tip 16 for convenience in rotating said screw, which rotation extends or withdraws the tool 11 with respect to the carriage 62. The arcuate engagement of the screw flange 14 and the tool shank 19 also prevents rotation of the tool 1|. To clamp the tool 1| in position, the carriage 62 is split as indicated at 11 and a clamping screw 18 is provided to draw the split portions tightly together about the shank 19, thereby preventing vibration and chatter in the tool 1| when work is in progress.

The lathe tool sub-assembly 58 is provided with clamping means adapted to secure said sub-assembly either to the frame 24 or to the casing of an automotive generator or motor in place in its installation. This clamping means comprises the offset piece '19 integrally formed with the carriage bed 59, the two transverse pins 88 and 81 projecting from the sides of said offset piece, the L-shaped stem 82 rotatably journaled in said offset piece,'and the wing-tipped lock nut 83 threaded upon an end of said stem. Figures 4 and 5 best illustrate the engagement of the sub-assembly 58 to the frame 24. To receive the aforementioned clamping means the lathe frame 24 is formed with the two upwardly and outwardly projecting fingers 84 and 85. These fingers 84 and 85 are spaced apart widely enough so that the offset piece 19 will 'fit therebetween but closely enough to engage the opposite ends of the transverse pins and 8!, In fastening the sub-assembly58 to the frame 24, the offset piece 19 is first positioned between the fingers 84 and with the pins 80 and SI abutting against the outside surfaces of said fingers. The L-shaped stem 82 projects between the fingers 84 and 85 with the foot of said stem extending over the inner surface of the finger 82. By rotating the wingtipped lock nut 83, the foot of the stem 82 may be brought to bear tightly against said inner surface of the finger El i, whereby the sub-assembly fit is firmly clamped to the frame 24.

Figures 2 and 3 illustrate how the lathe tool sub-assembly t8 may be mounted directly upon the casing of an automotive generator for work upon the commutator therewithin. Almost all automotive generators are constructed with an opening in the casings thereof directly over the commutator, like the opening 86 in the casing 81 of the generator 88 shown in Figure 2. This opening 86 is normally covered by a plate (not shown) but said plate is easily removable for access to the commutator 89. The ofiset piece is of my sub-assembly 53 is dimensioned to fit within the opening 86 with the transverse pins and Eli projecting from the sides of said offset piece engaging the outer surface of the casing 81 upon opposite sides of said opening similarly to the previously described engagement of said pins with the fingers 8:1 and 85 of the frame 2 A. The L-shaped stem 82 projects through the opening 35 and, by the tightening of the lock nut 83, is brought to clamp against the inside surface of the casing 81 as shown in Figure 3. The subassembly 58 is thus firmly mounted upon the generator 88 without the necessity of removing said generator from its installation. By rotation of the tool adjusting screw '12, the cutting tool H may be brought to bear upon the commutator 89. The engine of the vehicle in which the generator 88 is installed may be started up to rotate the commutator 89, and the carriage adjusting screw 83 may be turned slowly to move the tool 11 back and forth over said commutator until the worn and roughened surfaces thereof are properly turned down.

It is now apparent that my lathe tool subassembly 58 may be quickly and easily moved from a bench assembly as shown in Figure l to a portable application as illustrated in Figure 2 and vice versa. In the bench assembly of Figure 1, the armature 40 is turned by the belt 90 driven from the motor I2. The commutator 9| associated with the armature 40 is first turned down with the use of the lathe tool sub-assembly 58. When the worn surfaces have been refinished, the armature 40 is rotated slowly by hand to bring each strip of mica insulation between the commutator segments contiguous the undercutter tool 54. This tool 54 has previously been set, by means of the washer 5B and screw 51, to cut away said insulation slightly below the refinished commutator surface. As each strip of insulation is brought under the tool 54, the operating lever 5| is merely pressed forward to trim the strip of insulation all the way across the commutator and is then returned to initial position to clear the commutator for rotation to the next strip to be undercut.

Now, it will be perceived that I have invented a compact, highly efficient, yet simple and inexpensive apparatus for dressing the surfaces of worn and roughened commutators. The utility of my invention is greatly enhanced by the major sub-assembly thereof which may be quickly and easily removed from a bench installation of my invention and employed as a portable lathe tool adapted to be directly mounted upon an automotive generator in place in a motor vehicle and capable of trimming the commutator of said generator while the engine of the vehicle is running, thereby eliminating the otherwise necessary laborious and time-consuming task of disassembling and reassembling said generator.

Having thus fully described my invention and indicated its utility, I claim:

In a commutator dressing apparatus including a frame for rotatably mounting an armature shaft, said frame having a pair of spaced fingers projecting therefrom; a carriage and cutting tool sub assembly for turning down worn commutator surfaces, comprising: a fixed carriage bed; a tool carriage siidably mounted upon said bed; screw means for translating said carriage with respect to said bed; a cutting tool projecting from said carriage, said cutting tool having an arcuately slotted shank afixed thereto and journaled in said carriage; a tool adjusting screw threaded into said carriage parallel to said tool, said screw having a flange thereupon which rotatably engages said slotted shank for extending and withdrawing said tool with respect to said carriage and for preventing rotation of said tool; an offset arm projecting from said carriage bed, said arm being dimensioned to fit between said spaced fingers of said frame and also to fit within the annular slotted opening customarily formed over the commutator in automotive generator and motor casings; a plurality of pins projecting from each side of said offset arm, said pins being adapted to engage said spaced fingers and alternatively to engage the outside surface of said automotive generator and motor casings; an L-shaped stem threaded through said ofiset arm, whereby rotation of said stem may bring the foot thereof tightly against one of said fingers to clamp said sub-assembly to said frame and alternatively may bring said foot tightly against the inside surface of said generator and motor casings to clamp said sub-assembly thereto, thereby adapting said sub-assembly to function as part of a fixed bench assembly or as a portable device operable upon commutators of installed automotive generators and motors.

MILBURN MONTGOMERY ROSS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 459,572 Bonta Sept. 15, 1891 460,884 Nugent Oct. 6, 1891 1,366,784 Gardner et a1. Jan. 25, 1921 1,587,815 Boas June 8, 1926 1,786,442 Miller Dec. 30, 1930 2,061,398 Green Nov. 17, 1936 2,159,786 Errig et a1 May 23, 1939 2,281,307 Johnson Apr. 28, 1942 2,357,765 Rhindress Sept. 5, 1944 

